设计模式(1)-----简单工厂模式

简单工厂模式

　　简单工厂模式主要是为创建对象提供过渡接口，以便将创建对象的具体过程屏蔽隔离起来，达到提高灵活性的目的。

package com.csdhsm.designpattem.simplefactory;

/**  
 * <p>All rights Reserved, Designed By Han</p>
 * @Title:  Operator.java   
 * @Package com.csdhsm.designpattem.simplefactory   
 * @Description: 运算抽象类，提供抽象方法
 * @author: Han   
 * @E-mail: 294098789@qq.com  
 * @date:   2016年6月16日 上午10:48:44   
 * @version:V1.0     
 */  
public abstract class Operator {
    
    protected double num1 = 0;
    protected double num2 = 0;

    public void setNum1(double num1) {
        this.num1 = num1;
    }
    
    public void setNum2(double num2) {
        this.num2 = num2;
    }
    
    //抽象方法
    abstract public double calculate();
}

package com.csdhsm.designpattem.simplefactory;

/**  
 * <p>All rights Reserved, Designed By Han</p>
 * <p>For Taoyuan Web Application</p>
 * @Title:  FourOperations.java   
 * @Package com.csdhsm.designpattem.simplefactory   
 * @Description: TODO 
 * @author: Han   
 * @E-mail: 294098789@qq.com  
 * @date:   2016年6月16日 上午10:50:09   
 * @version:V1.0     
 */  
class OperationAdd extends Operator {
    
    @Override
    public double calculate() {
        return num1 + num2;
    }
}

class OperationSub extends Operator {
    
    @Override
    public double calculate() {
        return num1 - num2;
    }
}

class OperationMul extends Operator {
    
    @Override
    public double calculate() {
        return num1 * num2;
    }
}

class OperationDiv extends Operator {
    
    @Override
    public double calculate() {
        if(num2 == 0)
            throw new RuntimeException("除数不能为0!");
        return num1 / num2;
    }
}

工厂类

package com.csdhsm.designpattem.simplefactory;

/**
 * <p> All rights Reserved, Designed By Han</p>
 * @Title: Factory.java
 * @Package com.csdhsm.designpattem.simplefactory
 * @Description: 工厂类
 * @author: Han
 * @E-mail: 294098789@qq.com
 * @date: 2016年6月16日 上午10:33:48
 * @version:V1.0
 */
public class Factory {

    private static Operator operator;

    public static Operator getOperator(String type) {

        if (type == null) {
            throw new NullPointerException();
        }

        //根据运算符号获得对应的计算类(对字符串switch/case判断，只有jdk1.7以上版本)
        switch (type) {
        case "+":
            operator = new OperationAdd();
            break;
        case "-":
            operator = new OperationSub();
            break;
        case "*":
            operator = new OperationMul();
            break;
        case "/":
            operator = new OperationDiv();
            break;
        default:
            throw new RuntimeException("未能识别的符号!");
        }

        return operator;
    }
}

客户端代码

package com.csdhsm.designpattem.simplefactory;

/**  
 * <p>All rights Reserved, Designed By Han</p>
 * @Title:  Solution.java   
 * @Package com.csdhsm.designpattem.simplefactory   
 * @Description: 简单工厂模式
 * @author: Han   
 * @E-mail: 294098789@qq.com  
 * @date:   2016年6月7日 下午3:44:07   
 * @version:V1.0     
 */  
public class Solution {
    
    public static void main(String[] args) {
        double num1 = 7;
        double num2 = 0;
        String type = "*";
        
        Operator operator = Factory.getOperator(type);
        operator.setNum1(num1);
        operator.setNum2(num2);
        
        System.out.println(operator.calculate());
    }
}

总结：